As you learned in lesson 18, 12 Bar Blues is a pattern of chords which repeats every 12 bars and may be played in any key. You have already learned several examples of 12 Bar Blues. There are hundreds of well known songs based on this chord progression, i.e., they contain basically the same chords in the same order. 12 bar Blues is commonly used in Blues, Jazz and Rock. Some popular songs which use the 12 bar Blues form are:
Here is a 12 Bar Blues in the key of C. The pattern of chords will probably sound familiar to you. The left hand part is a walking bass line. This technique is common in Blues and Jazz.